[unreadable] To become a productive researcher, the applicant will be trained in quantitative/qualitative methodology and analysis and will continue training in adolescent substance abuse treatment. The purpose of this project is to incorporate skills learned in both settings to improve the health of adolescent substance abusers through: a) quantitative evaluation of the effectiveness of 12-step group attendance/affiliation on residential treatment outcome; and b) qualitative investigation of what aspects of 12-step groups are/are not helpful to change efforts. The proposed research builds on outcome data collected from 183 adolescents admitted to residential substance abuse treatment. An iterative mixed-methods design will provide a unique perspective from which to: 1) evaluate the quantitative relationship between 12-step group attendance and recovery environment risk, social risk, and frequency of substance use; 2) use participant observation/individual qualitative interviews to better understand the nature of 12-step affiliation; 3) conduct a quantitative analysis, followed by individual qualitative interviews, to identify predictors of 12-step affiliation/participation; and 4) develop programmatic strategies for increasing 12-step engagement. [unreadable] [unreadable] [unreadable] [unreadable]